1. Field of the Invention
The present invention relates to an ink jet recording material which is a recording material used for an ink jet recording system.
2. Description of the Related Art
As a recording material to be used for an ink jet recording system, there has been known an ink jet recording material in which an ink-receptive layer is provided on a support. The ink-receptive layer is roughly classified into 2 kinds. One is an ink-receptive layer comprising a water-soluble polymer as a main component, and the other is a porous ink-receptive layer comprising an inorganic pigment and a resin binder as main components.
The former ink-receptive layer absorbs ink into the water-soluble polymer by swelling. The latter ink-receptive layer absorbs ink in voids formed by the inorganic pigment. Due to such a difference in ink absorption mechanisms, the former is called as a swelling type (or a polymer type), and the latter as a void type (or a microporous type).
The swelling type ink-receptive layer gives high glossiness since it becomes a continuous and uniform coating film, but involves the problem that it is inferior in ink absorbability (ink absorption rate and drying rate after printing). On the other hand, the latter void type ink-receptive layer is excellent in ink absorbability and thus preferred.
As the inorganic pigment contained in the void type ink-receptive layer, there have been proposed to use inorganic fine particles such as fumed silica and wet process silica which had been pulverized and dispersed to have an average secondary particle size of 500 nm or less. Examples of using fumed silica may be mentioned, for example, JP H10-119423A, JP 2000-211235A, JP 2000-309157A, etc., and examples of using pulverized precipitation method silica may be mentioned, for example, JP H9-286165A, JP H10-181190A, etc. Also, examples of using pulverized gel method silica may be mentioned, for example, JP 2001-277712A, etc., and with regard to inorganic pigments other than silica, a recording material using alumina or alumina hydrate is mentioned, for example, in JP S62-174183A, JP H2-276670A, JP H5-32037A, JP H6-199034A, etc.
The above-mentioned void type ink-receptive layer has excellent ink absorbability, as well as excellent glossiness, image clarity, and coloring property by utilizing the inorganic fine particles having an average secondary particle size of 500 nm or less.
On the other hand, it has been generally known to use a paper support such as uncoated paper, art paper, coated paper, cast-coated paper, etc., a resin-coated paper which uses these paper supports as a base paper and at least one surface of which has been coated by a resin, or a resin film, etc., as the support of the ink jet recording material. However, these paper supports and the base paper for the resin-coated paper cause fine unevenness (hereinafter referred to as surface unevenness or “Menshibo”) at the surface thereof at the time of paper-making. When a porous ink-receptive layer containing the above-mentioned inorganic fine particles having an average secondary particle size of 500 nm or less is provided on a paper support having surface unevenness, or on a resin-coated paper in which at least one surface of a base paper having surface unevenness is coated by a resin, high glossiness, ink absorbability and image clarity can be obtained, but on the other hand, there is a problem of causing a feel of surface unevenness due to extremely high transparency of the ink-receptive layer itself. The feel of surface unevenness particularly and conspicuously appears as the glossiness of the recording material becomes high.
Various proposals have been made on a method for preparing a paper support or a base paper having excellent smoothness. For example, in JP S58-68037A, desired distribution of a fiber length has been proposed by a sieving method of pulp fibers obtained by beating of a pulp. Also, in JP S59-42295B, it has been proposed to regulate the starting pulp by its optical characteristics to solve the problem of smoothness, in JP S63-173045A, it has been proposed to formulate a pulp having a viscosity of the pulp of 5 to 12 centipoises, and in JP H6-67341A, it has been proposed a paper substrate which uses a bleached kraft pulp of hardwood (LBKP) and beats under specific conditions. However, each was not sufficiently satisfied.
It has also been known to use a matting agent in an ink-receptive layer of an ink jet recording material and has been disclosed in, for example, JP H11-321080A, JP 2001-341409A, JP 2004-1449A, JP 2007-125781A, etc. The above-mentioned feel of surface unevenness can be overcome by adding a matting agent to the ink-receptive layer, but glossiness, image clarity, and coloring property are lowered. Accordingly, it has been desired to develop an ink jet recording material in which the feel of surface unevenness has canceled without lowering glossiness, image clarity, and coloring property.
It has conventionally been known to use a pearlescent pigment for an ink jet recording material, and, for example, in JP 2004-276418A (Patent Literature 1), an ink jet recording material in which a silver white type pearlescent pigment is contained in a resin layer or an undercoat layer at the side of a resin-coated paper having an ink-receptive layer has been disclosed. Also, in JP 2004-276419A (Patent Literature 2), an ink jet recording material in which an interference color type pearlescent pigment is contained in a resin layer or an undercoat layer at the side of a resin-coated paper having an ink-receptive layer has been disclosed. Further, in JP 2003-80836A (Patent Literature 3), an ink jet recording material having a pearlescent layer containing a pearlescent pigment, a metal salt and a binder resin on a support has been disclosed, in JP 2005-288884A (Patent Literature 4), an ink jet recording material in which a pearlescent pigment is added to an ink-receptive layer mainly containing inorganic fine particles has been disclosed, and in JP 2006-218785A (Patent Literature 5), an ink jet recording material in which a pearl-like gloss layer is provided on an ink-receptive layer mainly containing inorganic fine particles has been disclosed.
However, these ink jet recording materials were each not a recording material which satisfy all of ink absorbability, glossiness, image clarity, coloring property and a feel of surface unevenness.
Also, a sheet-state ink jet recording material is generally cut to a predetermined size by a device such as a cutter, guillotine, etc., after an ink-receptive layer is continuously coated on a roll-state support in which a long support has been wound. However, in an ink jet recording material having a void type ink-receptive layer, the problems frequently occurred that powder of the ink-receptive layer which had been crushed at the edge portion accompanied by the cutting attached to a sheet (hereinafter referred to as powder dropping), and a sheet-state ink jet recording material slipped when it was transferred in a printer by transferring rollers to cause paper-feeding failure or paper output failure, or an image was not correctly printed due to the presence of powder attached to the sheet-state ink jet recording material. This problem was particularly and conspicuously occurred in an ink jet recording material having a void type ink-receptive layer which contained a pearlescent pigment.    [Patent Literature 1] JP 2004-276418A    [Patent Literature 2] JP 2004-276419A    [Patent Literature 3] JP 2003-80836A    [Patent Literature 4] JP 2005-288884A    [Patent Literature 5] JP 2006-218785A